Contact and method ojf making same



July 24, 1923. 1,462,609

' L. A. MAU

CONTACT AND METHOD OF MAKING SAME Filed June 16 1921 FETG'.4 E9. 6 FY161 14' FIGiO 17 4 Kfi 2 gg'yi mm 14;

I WITNESSES 484 VENTOR z W @XV/ Q ATTORN E Patented July 24, 1923.

,UNITED STATES PATENT OFFICE.

LOUIS ALBERT MAU, OE MILWAUKEE, WISCONSIN, ASSIGNOR 'IO MILWAUKEE AUTO ENGINE AND SUPPLY COMIPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

CONTACT AND METHOD OF IVLAKING SAME.

Application filed June 16, 1921.

To all whom it may concern.

Be it known that 1, Louis A. TVIAU, a citizen of the United States, and resident of ivlilwaukee in the county of lllilwaukee and State of Wisconsin, have invented new and useful Improvements in Contacts and Methods of Making Same, of which the following is a description, reference being had to the accompanying drawings, which are a part of this specification.

The invention relates to contacts for electrical ignition devices and to a method for making the contacts of the same.

The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclu sion hereof.

in the drawings: Fig. 1 is a side View of a commutator assembly of a timer provided with contacts made by the method embody" ing the invention, parts being broken away and parts being shown in section; Fig. 2 is a detail plan view of the commutator assem bly, parts being shown in section along the line 2-2 of Fig. 1; Fig. 3 is a plan view and Fig. l an end view of a rough contact blank; Fig. 5 is a plan view and Fig. 6 an end view of this blank after swaging to form a contact having pointed ends; Fig. 7 is a plan view and 8 a front end view of a finished blank for pointed end contacts; Fig. 9 is a plan view of a finished contact made from the finished blank shown in Figs. 7 and 8; Fig. 10 is a front end view and Fig. 11 a plan view of a finished cont-act having straight ends.

The commutator assembly includes a casing 10 a ring 11 of insulating material mounted therein and the contacts 12 inset in the ring and forming therewith a continuous circular trackway 13 upon which the brush, either of the circular or a sliding block type, runs, as well understood by those skilled in this art.

In Figs. 1 and 2 I have shown the contact 12 in the form of what will be referred to as the pointed end form of contact, while Figs. 9 and 10 show a contact having straight ends. In either case the method of making the contact is. similar.

A. piece of rectangular bar stock of appropriate thickness and width is put into a suitable punch press and crescent-shaped blanks 14 are punched therefrom. These Serial No. 478,093.

blanks which have rough edges, due to the punching operation, are then subjected to a swaging operation to bring them to finished size. The blanks 1d are preferably annealed prior to swaging to make this operation easier but this is not absolutely necessary. In the swaging operation for the contact having pointed ends, a bevelled edge 15 is formed on the outer side of the crescent. In either the pointed end or straight end contact a central depression 16 is formed in the back of the contact and surplus material, such as 17 shown in Figs. 5 and 6, projects from the face of the blank. The blank in this form is then placed in a trimming punch press to remove the metal 17 and the finished blank 14 of the contact having pointed ends or 1 1- for the straight end contact results from this trimming operation, as shown in Figs. 7 and 8 and 10 and 11, respectively. A screw threaded stem 18 is then welded to the finished blank with one end seated in the depression 16 to form the finished contact, shown in Figs. 9 and 11. The contact thus formed has a face 19 curved to conform to the radius of curvature of the ring 11. vVith the finished blank it he bevelling of the rear edge 15 produces pointed ends 20 and for this contact recesses 21 having bevelled rear edges are cut in the ring 11 in which the contacts have a nice fit, a pointed tooth milling cutter being used for this purpose. For the finished blank 14- recesses are also cut in the ring 11 in which the contacts have a nice fit by using a straight toothed milling cutter. A hole 22 is bored through the ring in the center of each contact-receiving recess, through which the threaded stem 18 passes. This stem, also passes through. insulating washers 23 and 2d and nuts 25 on the stems clamp the contacts in position in the ring and also hold the ring in position within the casing. The usual connections are made with the stem 18.

After the contacts are inset in the ring, a finishing cut is taken to bring the faces 19 flush with the inner surfaces of the ring 11 to form a smooth trackway, and annular grooves 26 are also preferably cut into the commutator ring so that the brush overhangs the trackway on each side thereof.

The finished blank 14, having the pointed ends, is particularly designed to permit the brush to ride partly on the contact and partly on the insulating ring during break-" ing, as more particularly described in c0nnection with the patent to Albert E. Smith, No. 1,371,940, dated March 15, 1921.

hat I claim as my invention is:

1. The method of making a contact for electrical ignition devices which consists in punching out a rough crescent-shaped blank from bar stock, swaging the blank to finished size and forming a depression in its rear side, trimming off the surplus metal, and welding one end of the threaded stem of the contact in the depression.

2. The methodof making a contact for electrical ignition devices which consists in punching out a rough crescent-shaped blank from bar stock, swaging the blank to form pointed ends on its operating face, trimming oil' the surplus metal, and attaching one end of the threaded stem of the contact to the finished blank.

3. The method of making a contact for electrical ignition devices which consists in punching out a rough crescent-shaped blank from bar stock, sWaging the rough blank to form a finished size blank with pointed ends on its operating face and a. bevelled rear face having a central depression, trimmin off the surplus metal, and welding one end of the threaded stem of the contact in the depression.

4. The method of making a contact for electrical ignition devices which consists in punching out a rough crescent-shaped blank from bar stock, swaging the blank to finished size, trimming off the surplus metal, and attaching one end of the threaded stem of the contact to the finished blank.

In testimony whereof, I afiix my signature, in presence of two witnesses.

LDUIS ALBERT MAU.

lVitnesses:

B. J. HAsKINs, E. R. EVANS. 

